Harlequin Duck Research and monitoring in Montana: 1997

Hendricks, Paul; Reichel, James

In 1997, we conducted Harlequin Duck pair surveys (including Glacier National Park) on approximately 73.5 km of 10 streams and found a minimum of 33 males and 25 females. Pair surveys during 1974-1975 and 1989-1997 in Montana have resulted in an observed sex ratio of 1.52:1 (m:f, n =786; 474 males:312 females). Brood surveys were conducted on approximately 114 km of 14 streams (including Glacier National Park) yielding a minimum of 13 females and 37 juveniles. Ten broods were produced on 7 of the 14 streams. Reproductive success on streams surveyed both for pairs and broods in 1997 (7 streams outside of Glacier National Park) averaged 0.30 broods per female (7 paired and 3 alone produced 3 broods) or 1.40 young per adult female (14 young produced among 10 females); average brood size at or near fledging (Class III) was 4.67 for these 3 broods (3.70 for the 10 broods observed in 1997). In Glacier National Park, McDonald Creek averaged 0.13 broods per female (11 paired and 4 alone produced 2 broods) or 0.60 young per female (9 young among 15 females). The Waterton River averaged 0.33 broods per female (3 pairs produced 1 brood) or 0.67 young per female (2 young among 3 females). Combined reproduction on 9 streams (0.21 broods per female, 0.89 young per female) was below the long-term average for the state and much below average for many drainages except the Sun River.